Two stroke engine with spring driven plunger

ABSTRACT

This invention is a two stroke, internal combustion, reciprocating, engine with plunger  14 , made up of a number of similar working units. Each working unit is comprised of cylinder  16  that is closed at one end by cylinder head  4 , and contains air inlet valve  2 , power piston  22  that is connected to power output shaft  26 , and plunger  14 . Plunger  14  is a movable wall with barrel  10  attached to it. Plunger  14  moves between power piston  22  and cylinder head  4 , and the means to accomplish this are: spring  12 , the urging of power piston  22  after a collision, and the difference between the internal and external engine pressures. During the compression stroke the pressure inside the engine exceeds the pressure outside of the engine, this pressure difference on the exhaust area forces plunger  14  up against cylinder head  4  and deforms spring  12 . During the expansion stroke the pressure difference continues to keep plunger  14  up against cylinder head  4  and spring  12  deformed. This condition will continue until the pressure force from the pressure difference on the exhaust area falls below spring  12  force. Near the end of the expansion stroke power piston  22  reaches pressure reducing chamber port  32 . When power piston  22  reaches pressure reducing chamber port  32  the pressure is reduced because of the added volume of pressure reducing chamber  8 , and the pressure force falls below spring  12  force. Spring  12  opens exhaust valve  6 . Since exhaust valve  6  is connected to plunger  14 , spring  12  resuming its undeformed state moves plunger  14  towards power piston  22 . While plunger  14  moves toward power piston  22  plunger  14  sucks in the working fluid and pushes the exhaust gases out of cylinder  16 . After the meeting of power piston  22  and plunger  14 , pressure reducing chamber port  32  is recovered and compression begins. To provide regeneration an alternating flow heat exchanger, called regenerator  30 , along with protector  34 , protector valve  36 , and protector check valve  38  are attached to plunger  14 . Protector  34  protects regenerator  30  from heat of combustion and removes regenerator  30  volume from the expansion process until the expansion pressure has fallen below the compression pressure.

BACKGROUND

[0001] 1. Field of Invention

[0002] The present invention relates to, reciprocating, two stroke internal combustion engines with plungers.

[0003] 2. Description of Prior Art

[0004] The approach taken in the past was to have the exhaust valve opened by a linkage from the power piston. This includes the present inventor in his patent application “A Two Stroke Regenerative Engine”, Ser. No. 09/658,927 dated Sep. 11, 2000. It also includes Warren (2000, U.S. Pat. No. 6,116,222) and Warren (2001, U.S. Pat. No. 6,199,520). What is needed is a new engine that opens the exhaust valve and moves the plunger without a linkage from the power piston. In some engines this occurs naturally when the pressure inside the engine gets reduced to an amount less than required to keep the exhaust valve shut. If a pressure reducing chamber is added to these engines, the pressure inside the engine would get reduced to an amount less than required to keep the exhaust valve shut every time the power piston opened the pressure reducing chamber port. The present invention has no linkage between the power piston and the plunger. The plunger is moved by a spring and by collision with the power piston and subsequent urging by the power piston, and pressure forces which compress the spring. A pressure reducing chamber is added to the engine to decrease the pressure force below that necessary to hold the exhaust valve closed. The pressure reducing chamber port is uncovered and recovered by the position of the power piston. The “Two Stroke Engine With Spring Driven Plunger” has no linkage between the power piston and the plunger.

SUMMARY

[0005] This invention is a two stroke, internal combustion, reciprocating, engine with a plunger, made up of a number of similar working units. Each working unit is comprised of a cylinder that is closed at one end by a cylinder head, and contains an air inlet valve, a power piston that is connected to a power output shaft, and a plunger. The plunger is a movable wall with a barrel attached to it. This plunger moves between the power piston and the cylinder head, and the means to accomplish this are: a spring, the urging of the power piston after a collision, and the difference between the internal and external engine pressures. During the compression stroke the pressure inside the engine exceeds the pressure outside of the engine, this pressure difference on the exhaust area forces the plunger up against the cylinder head and deforms the spring. During the expansion stroke the pressure difference continues to keep the plunger up against the cylinder head and the spring deformed. This condition will continue until the pressure force from the pressure difference on the exhaust area falls below the spring force. Near the end of the expansion stroke the power piston reaches the pressure reducing chamber port. When the power piston reaches the pressure reducing chamber port the pressure is reduced because of the added volume of the pressure reducing chamber, and the pressure force falls below the spring force. The spring opens the exhaust valve. Since the exhaust valve is connected to the plunger, the spring resuming its undeformed state moves the plunger towards the power piston. While the plunger moves toward the power piston the plunger sucks in the working fluid and pushes the exhaust gases out of the cylinder. After the meeting of the power piston and the plunger, the pressure reducing chamber port is recovered and compression begins.

[0006] To provide regeneration an alternating flow heat exchanger, called a regenerator, along with a protector and its valves is attached to the plunger. The protector protects the regenerator from heat of combustion and removes the regenerator volume from the expansion process until the expansion pressure has fallen below the compression pressure.

OBJECTS AND ADVANTAGES

[0007] Several objects and advantages of “A Two Stroke Engine With Spring Driven Plunger” are:

[0008] (a) The engine compresses the air in the same cylinder that the engine expands the air in.

[0009] (b) The engine compresses the air in a portion of the cylinder that is not heated by the hot gases.

[0010] (c) The engine saves the heat from the exhaust gases and releases the heat to the compressed air.

[0011] (d) The engine exhausts most of the exhaust gases each stroke.

[0012] (e) The engine can be operated so that the charge is almost fully expanded.

[0013] (f) The engine has no linkage between the plunger and the power piston.

[0014] (g) The engine is very efficient.

DRAWING FIGURES

[0015]FIG. 1 depicts the preferred embodiment of the invention at the start of the inlet and exhaust part of the cycle.

[0016]FIG. 2 shows the preferred embodiment of the invention at the start of the compression part of the cycle.

[0017]FIG. 3 shows the preferred embodiment of the invention during the compression part of the cycle as the plunger starts to move away from the power piston.

[0018]FIG. 4 shows the preferred embodiment of the invention at the start of the expansion part of the cycle.

REFERENCE NUMERALS IN DRAWINGS

[0019]2 air inlet valve

[0020]4 cylinder head

[0021]6 exhaust valve

[0022]8 pressure reducing chamber

[0023]10 barrel

[0024]12 spring

[0025]14 plunger

[0026]16 cylinder

[0027]18 fuel injector

[0028]20 igniter

[0029]22 power piston

[0030]24 connecting rod

[0031]26 power output shaft

[0032]28 plunger valve

[0033]30 regenerator

[0034]32 pressure reducing chamber port

[0035]34 protector

[0036]36 protector valve

[0037]38 protector check valve

DESCRIPTION

[0038] This invention is a two stroke, reciprocating, internal combustion engine employing plunger 14 as described herein. This invention employs a two strokes divided into three parts. The first part is the intake and the exhaust part. The second is the compression part, and the third is the expansion part. In the expansion part, power piston 22 moves from about top dead center to about 85% of its downward travel. The intake and exhaust part is from about 85% of the downward travel of power piston 22 to about 15% of the travel back up. The compression part is from about 15% of the travel back up of power piston 22 to about top dead center. The above positions are all estimates and are given for descriptive purposes only. The actual position a part of the cycle may begin or end at may be different from those set out above.

[0039] The working fluid that is expected to be employed in this invention is air; however, this working fluid could be any mixture of gases, liquids, and solids that can undergo an exothermic chemical reaction with the fuel. The working fluid that is introduced into the cylinder is sometimes referred to as air, or as the charge. After the combustion (or other exothermic reaction which provides the power for the engine) the charge is referred to as exhaust gases. The fuel may be any solid, liquid, gas, or combinations of these that can undergo an exothermic reaction with the working fluid.

[0040] FIGS. 1-4 illustrate schematically an internal combustion engine suitable for practice of this invention. Only one set of components for such an engine is illustrated; however, what is illustrated will function as a complete engine if it has an inertial load. It will be understood that this is merely representative of one set of components. A plurality of such structures joined together would make up a larger engine. Pressure reducing chamber 8 can be used by more than one structure. Other portions of the engine are conventional. Thus, the bearings, seals etc. of the engine are not specifically illustrated. The valves illustrated are but one type out of many that could be used. For example exhaust valve 6 could be a rotary disk valve: that when rotated counterclockwise opens and when rotated clockwise closes. Exhaust valve 6 can be any valve that spring 12 can open when it moves down and close when power piston 22 hits it moving up.

[0041] Cylinder 16 is closed at one end by cylinder head 4, and contains air inlet valve 2, exhaust valve 6, barrel 10, plunger 14, fuel injector 18, igniter 20, power piston 22, connecting rod 24, power output shaft 26, plunger valve 28, regenerator 30, pressure reducing chamber port 32, protector 34, protector valve 36, and protector check valve 38. Connected to cylinder 16 is pressure reducing chamber 8, and spring 12. Power piston 22 is connected to power output shaft 26 by a connecting rod 24 (for converting the linear motion of the piston to the rotating motion of the shaft). (A fuel injector is utilized for introduction of the fuel. While recognizing that this fuel may be introduced by other means, such a fuel injector is included here.) (A spark plug is used for ignition of the fuel. While recognizing that this igniter may only be required for starting.)

[0042] When air inlet valve 2 is open it allows air to be sucked into the cylinder volume located between cylinder head 4 and plunger 14. It can be any of a variety of valves including those referred to as check valves or one way valves. Fuel injector 18 can be anything that injects fuel into cylinder 16. Igniter 20 can be anything that ignites the fuel. Power piston 22 is a cylindrical piston that can move up and down in cylinder 16. The expanding gases exert a force on power piston 22 moving it down. That force is transmitted via connecting rod 24 and power output shaft 26 to a load (not shown). Cylindrically shaped plunger 14 is a movable wall that has a cylinder, barrel 10, connected to it. The diameter of barrel 10 on plunger 14 inside of the engine is one of the factors determining the expansion ratio of the engine. The diameter of barrel 10 also determines the force exerted on spring 12.

[0043] Spring 12 can be any energy storage means including a pneumatic spring device.

[0044] By placing regenerator 30 and exhaust valve 6 on plunger 14, plunger 14 forces the exhaust out through regenerator 30. Protector 34 protects regenerator 30 from the heat of combustion and also isolates the “dead” volume in generator 30 from part of the expansion process.

OPERATION

[0045] FIGS. 1 to 4 present the sequence of steps or processes occurring in “A Two Stroke Engine With Spring Driven Plunger”. The air intake and exhaust part of the cycle takes place between FIGS. 1 and 2. The compression part of the cycle takes place between FIGS. 2 and 3. Recouping the heat of exhaust takes place between FIGS. 3 and 4. The expansion part of the cycle takes place between FIGS. 4 and 1.

[0046]FIG. 1 shows power piston 22 at about 85% of downward travel. The engine has completed its expansion part of the cycle and is about to start the intake and exhaust part. When power piston 22 reaches the position shown, power piston 22 uncovers pressure reducing chamber port 32 releasing the pressure in cylinder 16 into pressure reducing chamber 8. Pressure in cylinder 16 drops below that necessary to keep exhaust valve 6 closed. As spring 12 opens exhaust valve 6, and moves plunger 14 toward power piston 22 exhaust gases are forced out of the engine through regenerator 30, cooling the exhaust gases and heating regenerator 30. At the same time air inlet valve 2 opens and air is sucked into the space between plunger 14 and cylinder head 4.

[0047]FIG. 2 shows the engine after plunger 14 and power piston 22 have come together. About the same time as power piston 22 met plunger 14 it recovered pressure reducing chamber port 32. Exhaust valve 6, plunger valve 28, and air inlet valve 2 have closed, and power piston 22 and plunger 14 will move up together deforming spring 12 and compressing the air between plunger 14 and cylinder head 4.

[0048]FIG. 3 shows the engine as power piston 22 nears about 85% of its upwards stroke. Pressure forces inside the engine, pressing on the area at the end of barrel 10, cause plunger 14 and regenerator 30 to move up to cylinder head 4. As the compressed air above plunger 14 is forced through regenerator 30, it heats up from the heat left in regenerator 30 from the exhaust gases.

[0049]FIG. 4 shows the engine after the fuel has ignited and the expansion stroke has begun. Protector valve 36 has been forced closed by contact with cylinder head 4. Protector check valve 38 is forced closed by the increase in pressure caused by combustion. The volume above protector 34 is now isolated from the expansion process. Power piston 22 will move down providing output power via connecting rod 24 and power output shaft 26. The difference between the pressure below protector 34 and above protector 34 will change as the expansion process takes place. At some time during the process protector check valve 38 will open allowing the “dead volume” pressure to join the expansion process. The difference between the pressure inside the engine and the pressure outside the engine will hold air inlet valve 2 closed and plunger 14 against cylinder head 4 until near the end of the expansion part of the cycle when power piston 22 uncovers pressure reducing chamber port 32.

[0050] The cycle repeats.

CONCLUSION

[0051] Accordingly, the reader will see that the two stroke engine with plunger meets the following objects and advantages:

[0052] (a) The engine compresses the air in cylinder 16, and the engine expands the charge in cylinder 16.

[0053] (b) The engine compresses most of the air in a portion of the cylinder above plunger 14 that is not heated by the hot gases.

[0054] (c) regenerator 30 saves the heat from the exhaust gases and releases the heat to the compressed air.

[0055] (d) Plunger 14 pushes out most of the exhaust gases each stroke.

[0056] (e) The diameter of the cylindrical part of plunger 14, barrel 10, causes the compressed volume to be smaller than in similar engines so that the engine will operate with the charge more fully expanded.

[0057] (f) the engine has no linkage between plunger 14 and power piston 22.

[0058] (g) protector 34 isolates regenerator 30 “dead volume” from the expansion process.

[0059] (h) protector check valve 38 allows some of the pressure of regenerator 30 “dead volume” to enter the expansion process.

[0060] Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.

[0061] Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given. 

I claim:
 1. A two stroke, internal combustion, reciprocating engine having a number of similar working units, each working unit comprising: a) a cylinder, closed at one end by a cylinder head and containing a movable power piston which moves in a reciprocating manner and is connected to a power output shaft; b) a plunger comprising a movable wall and a barrel, with said movable wall portion located within said cylinder and between said power piston and said cylinder head and with said barrel portion of said plunger extending through said cylinder head and forming an exhaust pipe, said movable wall of said plunger can be moved between said power piston and said cylinder head; c) an exhaust valve for exhausting the exhaust gases located on said plunger to permit the flow of exhaust gases from said cylinder when said plunger moves towards said power piston, and prevent the flow of exhaust gases from said cylinder at all other times; d) a one way flow means located on said plunger to prevent flow through said plunger when said plunger moves towards said power piston, and allow flow through said plunger when said plunger moves towards said cylinder head; e) a means for storing energy during the expansion part of the cycle for use in moving said plunger during the exhaust and air intake part of the cycle; f) an air inlet valve for permitting the flow of fresh working fluid into said cylinder during the time during each operating cycle that said plunger moves toward said power piston; g) a pressure reducing chamber that when opened to said cylinder increases the volume of said cylinder thereby reducing the pressure in said cylinder; h) a means for opening said pressure reducing chamber into said cylinder; i) a means for increasing the temperature of the compressed gases; j) a thermal regenerator; said regenerator being an alternating flow heat exchanger which moves with said plunger between said cylinder head and said power piston, and stores heat from exhaust gases as it moves towards said power piston, and releases heat to the compressed air as said regenerator moves away from said power piston; k) a regenerator protector; l) a protector valve in said regenerator protector that is open whenever said plunger is away from said cylinder head and closed when said plunger is adjacent to said cylinder head; m) a check valve in said regenerator protector that is open only when the pressure above it exceeds the pressure below it;
 2. An engine as recited in claim 1 wherein said one way flow means is a valve.
 3. An engine as recited in claim 1 wherein said means for storing energy is a spring.
 4. An engine as recited in claim 1 wherein said means for opening said pressure reducing chamber into said cylinder is a port in the wall of said cylinder.
 5. A process for operating the engine of claim 1 having the following steps: a) said power piston moves down as a result of pressure created by the increasing temperature of the compressed gases; b) said protector check valve is forced closed by air pressure; c) said power piston delivers output power; d) said protector check valve is forced open by the compressed air pressure trapped in the regenerator, and the trapped compressed air volume joins the expansion process; e) at about 85% of the downward travel of said power piston, said power piston uncovers said pressure reducing chamber port; f) pressure in said cylinder drops; g) said exhaust valve is opened by said means for storing energy; h) said one way flow means is closed; i) said plunger starts to move down; j) said protector valve opens; k) said air inlet valve opens; l) said plunger continues to move down sucking in fresh air and pushing out exhaust gases; m) the exhaust gases going out heat up said regenerator; n) said power piston starts back up; o) said power piston and said plunger meet; p) said power piston forces said plunger upwards; q) said exhaust valve is closed; r) said one way flow means is closed; s) said air inlet valve is closed; t) the air is compressed; u) the compressed air pressure forces said plunger up against said cylinder head; v) as said plunger moves up against said cylinder head, the compressed air moves through said regenerator and heats up; w) said protector valve closes; x) said power piston reaches the top of its travel; y) said means for increasing the temperature of the compressed gases increase the temperature of the compressed gases; z) the cycle repeats. 